1. Technical Field
The disclosure relates to an endoscope system configured to be introduced into a living body to capture an image inside the living body, and a pixel correction method for correcting a pixel of an image sensor provided at the endoscope system.
2. Related Art
In the related art, a solid state image sensor such as a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS) is formed of a plurality of pixels that outputs electric signals by receiving light and photoelectrically converting the light. In this kind of solid state image sensor, it is known that there may be a defective pixel that outputs an abnormal electric signal not associated with a receiving amount of the light. Kinds of such defective pixels may include: a constant defective pixel that constantly outputs an abnormal electric signal due to dust adhesion to a light receiving surface, a device crystal defect, and the like; and a blinking defective pixel that irregularly outputs an abnormal electric signal due to noise of a random telegraph signal (RTS) generated by current disorder caused by a fact that electrons moving inside a MOS transistor are captured by a trap level existing in a gate insulator film due to miniaturization of the solid state image sensor.
The blinking defective pixel appears on a captured image as image noise irregularly generated while a moving image is photographed. As a technology to remove such image noise, there is a known technology in which the solid state image sensor is made to capture images a plurality of times in a state that an image sensor is blocked from the light, and a blinking defective pixel is detected from a plurality of captured images, and then an electric signal of the detected blinking defective pixel is corrected (refer to Japanese Laid-open Patent Publication No. 2013-211785).